Jasper Stein's old mother Elisabeth has a fatal cardiac crisis while he takes her on a yacht trip. Jasper and wife Sonja's curious attitude seems to confirm Cornelius's suspicion that it may not be a natural death, which the coroner rules. Against Grubers' orders to back off, Kai and Ben reluctantly help check out a mistaken identity theory. Meanwhile Holger leads the official investigation about inexperienced Lithuanian captain Leonas Paulauska's suspicious voyages, which links to the Stein case.
—KGF Vissers